In the manufacture of rolled web products, such as bath tissue or paper towels, a winder winds a web of material to form a large parent roll. The parent roll is then subsequently unwound, subjected to a variety of conversions, such as embossing, and then rewound by a rewinder into a consumer diameter sized convolutely wound log. The convolutely wound log is eventually cut into consumer width sized rolls, such as bath tissue, paper towels and similar finished products. To efficiently process the convolutely wound log through converting processes, cutting and packaging, the loose end of the log (i.e., the tail) is often secured or sealed to the body (i.e., the non-tail portion).
Common gluing, moistening and other systems known to those in the tail gluing art typically require some manipulation of the tail for correct alignment in adhesive application, proper winding or rewinding and the like. In most commercially available embodiments, the tail is laid flat and unwrinkled against the log with the tail being secured to the log at a position a short distance from the very end of the tail. This tail sealing arrangement leaves a small length of the end of the tail unsecured (the so-called “tab”) to enable the end user to grasp, unseal and unwind the convolutely wound product.
Known methods and systems for tail sealing face many undesirable results. For example, many systems dispense excess adhesive that is not picked up by the convolutely wound roll. Such excess adhesive is often recovered in an underlying tank and made to flow back into the system. Other known systems incorporate a bath or pool of adhesive which is provided in an open condition. In both situations, the systems allow dust, debris and other foreign matter to be incorporated into the adhesive, thus polluting the adhesive flow stream and/or reducing the effectiveness of the adhesive upon subsequent rolls. Such systems typically incorporate filtration systems in an effort to remove such pollutants from the adhesive stream. Such filtration systems add increased cost to the systems as well as provide routine maintenance issues.
Many known systems also have been found deficient when attempting to obtain a sufficient amount of adhesion. Adhesion problems may arise due to substrate specifications and enhancements, such as high topography or strength-inducing chemicals. Modern papermaking and embossing techniques have been able to provide web substrates that have a high degree of deflection in the direction orthogonal to the plane formed by the web substrate. Many known systems can utilize only the portions of the substrate having a high degree of deflection as a suitable bonding area because the portions of the substrate having a low degree of deflection are unavailable or less available to serve as contact points between surfaces sought to be connected. This limited bonding area has resulted in insufficient adhesion because of limited opportunities for adhesive contact. Strength-inducing chemistries utilized in producing paper web substrates also contribute to adhesion issues. Manufacturers are increasingly incorporating strength-inducing chemicals to substrates to enhance quality. Yet, such chemicals may interfere with the bonding of adhesives in tail sealing.
Further, adhesion issues have arisen from the type of adhesive and method of application. Indeed, known systems often emit adhesives in such a manner that the adhesives penetrate below the surface of the paper web substrate as opposed to residing on the surface. Adhesive absorbed below the surface results in less adhesive being available for bonding at the surface and therefore less adhesion.
Moreover, known tail gluing systems often utilize adhesive that dries slower than desired. It is desirable that tail seal adhesive dry quickly, so that the bond is set in time for downstream converting operations (e.g., wrapping, bundling, etc.). A log typically is processed through such processes in about 5-10 minutes. Yet, known systems utilize adhesives with drying times of more than an hour—which fully dry long after the product is cycled through the manufacturing processes. In such cases, manufacturers often rely on temporary bonding primarily attributable to cohesive bonding within the adhesive, which is typically substantially lower than the final strength of the adhesive when it is fully dried (i.e., after sufficient time has passed to achieve maximum bonding).
Insufficient drying and/or bonding also can occur based on heavy localized application of the adhesive, where the adhesive is concentrated in particular areas due to the application design. The formulation of the adhesive may contribute to adhesion problems as well, with many typical formulations containing about 85% to 97% water. Water not only inhibits drying but also interferes with bonding.
The lack of sufficient adhesion produces manufacturing problems such as tearing, wrinkled tails, unsightly bonding areas and/or delays in production due to loose tails. To compensate for deficient bonding, manufacturers have over-applied adhesive to the tail to create some sense of quick adhesion, which is mostly due to the internal cohesive strength of the glue itself. Yet, this can result in negative end user feedback because, once the adhesive completely dries, the tail becomes difficult to remove from the roll and can cause the separation of plies and/or tearing of sheets.
In addition, tail sealing processes struggle with precise placement of adhesive to create the tab of the tail and ensure the roll does not become unsightly due to the tail sealed portion.
Thus, it would be advantageous to provide for a tail gluing system that addresses one or more of these issues. Indeed, it would be advantageous to minimize or even eliminate the prospect of contamination of the adhesive. It would also be useful to provide for a tail gluing system that increases adhesive efficiency, such that it provides sufficient bonding for substrates having high surface topography (despite the limited available bonding area) and/or substrates with strength-inducing chemistries. Likewise, it would be beneficial to provide for a system that reduces both the amount of adhesive required and the drying time necessary to provide suitable bonding. Additionally, it would be beneficial to provide a tail sealing system that reduces negative end user feedback and/or allows for adhesive to be applied in a pattern. Finally, it would be advantageous to provide for a tailing sealing system that increases throughput, reduces the components required to operate effectively and provides for a mechanism that reduces the maintenance required upon such a tail gluing system.